


Freestyle

by tsukinofaerii



Series: Learning to Swim [5]
Category: Teen Wolf (TV)
Genre: Families of Choice, Knotting, Multi, Pregnancy, Season 3 Didn't Happen, Semi-Public Sex, Threesome - F/M/M, Xenophilia
Language: English
Status: Completed
Published: 2014-10-09
Updated: 2014-10-09
Packaged: 2018-02-20 11:29:33
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 9,612
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2427068
Author URL: https://archiveofourown.org/users/tsukinofaerii/pseuds/tsukinofaerii
Summary: <blockquote class="userstuff">
              <p>It's the last full moon of the summer before Stiles and Allison have to go back to school. Derek plans to make the most of it.</p>
            </blockquote>





	Freestyle

**Author's Note:**

> (baseball slides in) 
> 
> This one is a little different than the xenophilia I've done before, but hopefully the POV switch will work! Many, many thanks to the amazing poisontaster, who did a bang-up job betaing this for me on short notice.

Dim sunlight slanted into the bed area lazily and across Derek's eyes, dulled by the screens around the bed. The moon tugged at his bones restlessly but it was still just a suggestion, not the enraged demand it would be later. The sheets were a little too stiff, too scratchy, against his moon-sensitive skin but not so much as to be impossible. 

In the kitchen Stiles was trying to be quiet while he made coffee, which meant absolutely nothing to a werewolf. Every clink and footstep was loud as if it had been in the same room, and the scent of brewing coffee was heaven. Outside birds chirped lazily, the morning commute having settled into the usual faint grind of distant motors. 

Above all that, the steady beat of two familiar hearts filled the gaps in the silence. There was more, though. A muffled, tripled rhythm at the very edge of hearing. 

Derek snuffled into the back of Allison's neck under her curls, breathing her in. She smelled _right_ —a mix of him and Stiles, an edge of fur, and a faint touch of something that he thought might be her pregnancy. Her heartbeat was soft and even but even in sleep, she was slightly tense. One of her arms curled up under her head, resting near a spot in the headboard that had lately started to smell like metal and gun oil 

Carefully, he dragged his fingers across her forearm, up to her hand. When she didn't immediately try to break his wrist, he moved her hand down. Without so much as a blip in her heartbeat, she twisted her wrist around to lace her fingers through his. Her grip was a little tight, nails a little sharp, but Derek just squeezed back until her hold loosened again. 

After that he started drifting off again, lulled by comforting scents and sounds. He'd shuffled his schedule around to get the last full moon before Fall Semester off from work and he didn't want to wake up early if he didn't have to. 

It worked until something sizzled, and the scent of frying fat overrode the coffee. Allison's head on his arm came up and Derek saw her nose twitch. 

"Bacon?" she murmured sleepily, sniffing again. 

There was a faint ring of mascara around her eyes where she hadn't quite cleaned it off. Derek ran his thumb over it gently, getting his palm nuzzled in return. "Smells like it," he answered. "Do you want me to bring it to you?"

Allison hummed and stretched, arching her back until her joints popped. Then she collapsed, rolling over to wrap her arms around his chest. Warm skin pressed against his side, from his ribs down to his knees. "Carry me to the bacon?" Sleep-gummed eyelashes batted coquettishly.

"You can walk," he reminded her. "Walking is even good for you."

She grinned, but she was still asleep enough that it was lopsided and a little damp. "I know."

Heaving a put-upon sigh, Derek tried to roll free of her, but got caught when she tightened her arms around him. "You have to let me go if you want me to carry you," he reminded her, poking her hip. She just muttered something inaudible even to werewolf ears and squirmed closer, eyes starting to drift closed. 

"Allison..." Derek pressed a kiss to the corner of her mouth. Mostly asleep or not, she still turned into it, mumbling appreciatively. He kissed her again, deliberately brushing close enough that his beard scraped her skin. A shiver ran down her, loosening her hands on his hips. Before she could get ahold of him again, Derek lifted her hands off him, tucking them up against her chest. There was an extra sharpness to her nails when he lifted them off his hip that he tried not to think about too much. If the worst happened, he hoped Allison understood wolves better than her mother.

Once he'd won free, Derek wrapped Allison up in one of the sheets and picked her up. She sighed and curled up against his chest with her head on his shoulder. He shuffled her higher, so she wasn't breathing right over his pulse, and carried her out.

Towers of boxes had been reduced to piles that Derek weaved through, exercising the delicacy of motion that came with stubbed toes after midnight. The main area of the loft was still riddled them, but not as badly as it had been three weeks before. Most of Allison and Stiles' things had found permanent places to be stored. All that was left were the things they'd be taking back to school with them in less than a week. 

That was something else Derek tried not to think about. He'd been doing a lot of not thinking lately. It was either that or end up running naked through the woods in panic again. One time explaining to the Sheriff was enough. 

For some reason Stiles had made the extremely questionable decision to cook bacon in only a pair of boxers. The cost of that was already visible on his arms and chest in places where the grease had splattered and left tiny burns. It didn't seem to bother him, though. He danced around, flipping the meat with precision focus. Already there was a plateful of it, along with a bowl of batter and a carton of eggs. 

Derek hooked one of the stools with his ankle and pulled it under him, settling carefully with Allison on his lap so they could watch Stiles cook. There wasn't much in Stiles' repertoire, mostly fried and breakfast foods, but what he made was always edible. "Could you pour me some coffee? My hands are full." 

"Yeah, sure, just give me a—" Stiles looked up and his heartbeat immediately skipped into high gear. Faster than Derek could follow, he'd flipped the burner off, moved the pan aside and was already reaching for the first aid cabinet. "What's wrong? Is she sick?"

"Lazy," Allison muttered, rolling her head to smile. "I didn't want to give up my bed partner. He's warm."

"Yeah, I can see why you wouldn't want to do that." The frantic patter of Stiles' heart slowed, though not quickly. He turned on the stove, put the pan back on the burner, then grabbed a piece of bacon from the plate. "Open." Obediently, Allison opened her mouth and Stiles popped the bacon in. 

She chewed thoughtfully while Stiles poured Derek's coffee. When he came back with the coffee, Allison's mouth snapped open and was gifted with another piece of bacon.

"I could get used to this," she mumbled, licking bacon grease from her lips. 

"You're taking advantage of the situation," Derek accused, accepting his mug from Stiles with a quick smile. 

"Damned right I am." The meat revived Allison from her early morning doziness. She wiggled her way upright, watching Stiles eagerly as he returned to cooking. Every now and then, he'd take a piece of bacon and lean back to give it to her. A few times she tried to use her hands, but Stiles withheld the bacon until she finally just opened her mouth again. Then they both gave Derek smug looks. 

He pretended not to see. A man had to have some dignity. 

After the bacon was piled high, Stiles moved over to plug in a waffle maker Derek hadn't even realized they owned. "So, what's our plan tonight?" Stiles asked, shifting his weight to scratch the back of his calf with a toe. A spoon clinked as he did something with butter and vanilla that smelled slightly different than it should have with just those two ingredients. "Erica's not going to be happy if we just sit at home and watch TV on our last full moon in Beacon Hills this summer, and Scott needs a distraction ASAP. He's been texting nonstop me about what colors we want in the nursery." 

"What did you say?" Allison asked suspiciously. Her nose wrinkled. "You better not have said alpha red, Stiles." The answer was suspicious silence, and a focus on fluffing the batter that waffles didn't deserve. "Stiles. _Stiles_ , no. You didn't!"

"But it's a good color!" he finally whined. "And what was I supposed to say? We haven't decided on colors? Or names? Or _it's barely the second trimester, Scott, you're scaring me_?"

"Yes!" Derek and Allison snapped together.

"Besides, they'll be betas. Red wouldn't work," Derek added, because it was true. "If Scott really wants to buy things, tell him to get blankets or something. Or take up knitting."

"Toys," Allison added thoughtfully. Her heel tapped against his thigh pointedly. "Toys don't have a color scheme to worry about, and we'll need things to survive claws."

Batter sizzled as Stiles poured it in, filling the air with the scent of vanilla and, faintly, burnt toast. He didn't say anything until the first set of waffles were done and flipped onto the plate. "So we're still avoiding the nursery question? Because I kind of hoped we could solve that before we leave next week." 

"Maybe we should look at the bedroom again," Derek admitted reluctantly. "It's safe now."

No one responded. Stiles poured batter for more waffles, heartbeat skipping an erratic, nervous drum solo. Allison squirmed uncomfortably on Derek's lap. 

"Yeah, I guess," she muttered eventually, ducking down so she was more buried in the sheet. "Or maybe we should... look at other places?"

Derek realized he'd gone stiff only when Allison did, too. He tried not to be one of those territorial alphas, but the thought of leaving his home—even for a good reason—made his teeth sharpen. The pull of the moon played over his skin, urging him to change, to shred anyone who would threaten his den. He made himself relax, letting the scent of food and family and lazy summer mornings bury the feeling. 

"We could do that," he agreed, as mildly as he could manage. "Why don't we look at it today, and see if Deaton has any ideas? Maybe we'll feel better if we repaint it or something."

"If we let the others repaint it, you mean." Allison still smelled unhappy with the offered solution but, when she tipped her head up, it was to smile. "They really want to help. May as well take advantage of the free labor." 

"Or we could save it for when we really need it, like after the kids are born," Stiles put in. 

The tension dissipated somewhat as they picked up the thread, Allison and Stiles tossing jokes back and forth about how much they were going to take advantage of the Sheriff, baiting him and Melissa with favored grandparent status. The scent of bacon was joined by waffles and, eventually, fried eggs as Stiles fought for pro-Boyd no-Erica babysitting rules.

Derek rested his chin on Allison's head, closed his eyes and let himself doze again.

* * *

After breakfast, they all put on clothes and went upstairs to investigate the formerly haunted bedroom. Or, more accurately, Derek went upstairs while Stiles and Allison hovered halfway up the steps behind him, armed respectively with a broom and a machete. 

"I feel so reassured," Derek muttered, climbing the spiral staircase one slow step at a time. His claws scraped the metal rail every time he let them slide. He hadn't put his shoes on and his toe claws kept catching when he stepped wrong. But he didn't put them away. "Big, bad werewolf hunters going to protect their alpha. Right." 

"You're the one who can heal!" Stiles called back from the brave space of one step in front of Allison. "Just scream if the dresser charges and we'll call for help!"

Derek rolled his eyes and took the last step onto the landing. They didn't see it, but it made him feel better. 

The entire floor smelled of dust and abandonment, thick, stale air where Derek had blocked off the vents. There were, technically, two bedrooms according to the floor plan. At some point in the past the wall between them had been mostly knocked down, leaving a waist-high brick stump behind that was simultaneously too short for a wall and too thin for a bar. 

There wasn't that much furniture. A California King bed, a dresser, a mirror and the trunk he kept the chains in. When the possession happened, not having too much furniture had been a surprisingly bad thing. Apparently, evil spirits needed space to work in; murderous spirits did a lot more damage when they could get a run up. The dents in the wall and the boarded-up window were evidence of that. There would have been bloodstains, but the furniture had absorbed them. 

Derek made a thorough search for any sign that the furniture might have been independently mobile since the casting out. The dust was still in place, with the exception of the path he and Stiles had cut getting the mattress for their movie night earlier that month. There was no smell of sulfur either, which had been the big clue that something had been wrong. 

"I think it's—" Derek's voice fell as he turned and saw Stiles and Allison crowded into the doorway behind him, "—safe. Are you two sure you're willing to risk it? Maybe it's possessing the dust now." 

Stiles made a face at him, broom resting loosely in the crook of his arm. "I have one of Scott's old asthma sprays. I'll be fine." 

Machete held low but ready, Allison inched in, looking around thoughtfully. "We'd have to get rid of most of this stuff anyway," she said off-handedly, casting a look at Stiles and Derek over her shoulder. "That window would make it nice and bright during the day. Airy." 

It felt like an offer of a compromise. "We could rebuild the wall," Derek suggested. His arms crossed, then uncrossed when that felt too standoffish. "Move the bed up from downstairs." 

"If we're going to start sleeping up here, we're going to have to remodel the shower," Stiles opined. Wood scraped as he used the handle of his broom to nudge the door of the upstairs bathroom through the doorway. Inexplicably, it only featured a shower and a sink, not even a toilet. Derek only bothered with it when he was bloody and didn't want to risk ruining the good bathroom. After the possession, not even for that. "I don't think any of us want to try and juggle messy toddlers downstairs, right?" 

That word sunk down into Derek's stomach. _Toddlers. Right_. Toddlers. Children. _Teenagers_. It was easy picturing the routine they'd need with infants, but they had to plan for the actual future. Sometimes he still forgot he needed to do that. He'd spent too many years assuming he wouldn't get one. 

"Maybe we should think about moving." 

Two startled stares landed on him. With the full moon so close, it felt like an actual touch on his skin, a breath of surprise. 

"This place isn't really suitable for a family, especially not one of wolves," Derek continued, finally giving in to the urge to cross his arms. "We'll have to do a lot of remodeling just to get it ready for the nursery. What are we going to do when they're fifteen? Six people in two bedrooms isn't reasonable." 

By the way Allison and Stiles looked at each other, they'd been thinking the same thing and neither one had wanted to say it. 

"But it'll do for now," Allison said gently. She set her machete down on the floor and crossed the few feet to touch his arm. "For a few years, at least. Not everything has to change all at once."

He shrugged. Fought the need to lean into her touch. "Maybe it should."

It didn't feel right even thinking it. Derek had bought the building when he'd accepted that he was going to die in Beacon Hills. Maybe not immediately, but soon enough. It was supposed to be a place to build his army, to train a pack to fight off whatever came. Something to leave them when the fight was over. And then the fight was over, and he'd been inexplicably still standing. Alive. 

Before anyone could say anything too uncomfortable, the buzzer jangled down below. Derek pulled away from Allison's hand and side-stepped Stiles' worried touch as he slipped through the door. "Talk about it. I'll see who it is." 

They didn't follow, for which he was a little grateful. Even with a change of subject, he needed space. 

The door opened to a sight he shouldn't have been surprised by. "Argent." Derek crossed his arms and leaned in the doorway, deliberately blocking it. Allison had, as far as Derek could tell, forgiven her father for the mess after the ultrasound. Derek didn't have that much mercy in him. "Here for Allison?" 

"That too." Chris Argent smiled tightly, not showing teeth. He hadn't bothered to shave that morning. It combined with his flannel shirt to make him look like a mountain man come down from the hills. The five large plastic containers at his feet ruined the effect somewhat. They smelled like meat and a hint of the gun oil that followed Argents everywhere. "I know your— pack," he grimaced a little at the word, "is going to be busy tonight, so I thought stop by early, drop off some food I made." 

"Very thoughtful of you." Flexing a shoulder, Derek pushed himself back upright. "I'll go get Al—"

"Wait!" Argent grabbed his arm before he could actually turn. "Can I talk to you first? Just for a minute." 

Derek paused, eyebrows rising as he looked down at Argent's hand on his arm, then back up at the man himself. His skin rippled subtly, fur wanting to sprout, teeth to grow and stretch. He let his eyes flash red, coloring the world bloody. It never hurt to remind Argent of what he was dealing with. "If you're going to ask about our sex life, I'll throw you down the stairs and apologize to Allison for it later. She'll even forgive me, maybe."

A dull red flush colored Argent's cheeks and he moved his hand. "That won't be necessary," he said, with admirable control. "I just... How is she doing? What's your opinion as her," Argent's entire face twisted, lemon sour and resenting it down to his bones, "alpha?"

"Not just as one of her mates?" Derek found deep pleasure in the way Argent's expression crumbled even more at the reminder. 

"Is that what you people call it?" There was no missing the disgust in Argent's voice. Heavier in it was something even more interesting, though: guilt.

It was enough to make Derek's hackles settle a little. At least Argent wasn't completely oblivious. Derek could work with that. "No," he admitted, eyes fading back into human colors. "Not usually. I grew up around humans too, you know." 

"Point taken." The guilt intensified, hidden in the set of Argent's shoulders, but not in his scent. "But you didn't answer my question. How is she?" 

Derek chewed it over. Upstairs was suspiciously quiet—he never would assume Allison and Stiles would refrain from listening in. It was the exact opposite of both of their natures, and Allison especially deserved to be involved in everything that her father was. Whatever he said would matter more than just to soothe Argent's feelings. "She's still human, if that's your concern," he started slowly. "There's signs, but Deaton warned us about them. We're all being careful." 

"Careful enough?" Argent bit out, then immediately winced. "I'm sorry. I don't— know how this goes. There's nothing in the lore about it."

"Hunter women never slept with the enemy before?" Derek couldn't stop himself from asking. The question tasted bitter. Upstairs the silence turned heavier; they were holding their breaths. "You can't tell me Allison's the first. We both know better than that."

"The first to keep the baby," Argent admitted. "Usually by the time it got this far, she'd have left the family. This is unprecedented." 

For a second, Derek considered kicking Argent out entirely. By the way Argent's weight shifted to brace himself, he must have expected exactly that. Allison probably wouldn't even say anything. If anyone would understand, she would. 

That didn't make it right, though. 

"There has to be a first, sometime. Come on in." Derek bent down to pick up the food at Argent's feet. It mostly smelled like meat. Venison, some beef, lamb. Maybe a hint of potato or a green whiff of vegetables, but mostly meat. "I'll take this to the kitchen. She's upstairs with Stiles." 

Gratitude lit Argent's eyes. He nodded, following Derek into the loft and looking around curiously. His eyes never strayed toward the screens that sectioned off the bed. "I won't stay too long. I know you've probably got plans." 

"We can always take time out for food." Allison appeared at the top of the stairs, grinning widely, followed by Stiles. Metal rattled as she stomped her way downstairs, pausing for a anxiety-scented second before throwing herself at her father for a hug. "Is that shepherd's pie? It smells like shepherd's pie." 

Derek laid the containers on the counter and cracked open the top one. "Looks like more shepherd than pie." He tried to keep his tone level, though he couldn't quite manage to suppress a flare of annoyance. Allison _had_ been eating a lot of meat lately. That didn't keep it from feeling like a pointed jab. "What, did you only use one potato per deer?" 

Unexpectedly, Argent's expression fell. He swallowed and looked down at Allison with a weak smile. "When Victoria was pregnant with Allison, she craved red meat constantly," he explained quietly. "I figured it wouldn't hurt." 

"I just thought it was a werewolf thing," Stiles said, a little too casually. He elbowed Derek as he brushed past him toward the cabinets with the bowls. It wasn't quite lunch time yet, but the way Allison's nose twitched toward the kitchen meant that probably didn't matter. "Are you going to eat with us? We're trying to decide what to do about a nursery setup before we go back to school. You've got experience with this stuff, right?"

"I don't know..." Argent glanced at Derek questioningly. His arms were still around Allison's shoulders, fingers curled in her shirt. It was just a step short of clinging. "I don't want to get in the way."

Stiles' elbow was back in Derek's side, grinding in sharp and painful as he made a show of filling bowls. Not that it was necessary. "Stay," Derek said quietly. "We're going to be family now, right?"

The look Argent gave him pure relief, even if his smile was weak. "I suppose so."

* * *

The rest of the day failed to be completely terrible. Argent stayed for most of it, providing unexpectedly good advice on the nursery issue. He agreed that the loft wouldn't work for the long term, but pointed out that there really wasn't time to house hunt before Stiles and Allison went back to school, and house hunting toward the end of the pregnancy would be a nightmare.

"What you need to do is renovate the entire building," he said, tapping a finger on the blueprints that were taking up most of the bar "Start with your unit, then expand out. You can stay here for a few years, then start renting units when you're ready to move. It'll be a steady source of income."

"We don't exactly need the extra income," Derek reminded him flatly.

"Then you can flip the place to someone who _will_ rent it and turn a profit off the upgrades," Argent shrugged. "Put the money in a college fund. They're tax deductible and in twenty years you'll be glad you did it, believe me." 

So that was that. 

When Allison walked her father to his car, it was nearly five in the afternoon, the clock inevitably ticking its way to moon rise. 

Derek dropped onto the couch next to Stiles, who obligingly shifted so Derek could take most of the couch and his lap. He could hear Argent and Allison talking as they took the elevator, the steady double-beat of their hearts. Even though he knew better, he couldn't keep from focusing on them, even when they got distant enough to make it difficult. 

Argent had been a pleasant enough guest. There'd been minimal sniping, no actual arguments. Everything he'd said had been mostly reasonable. Part of Derek was still waiting for him to try something, though. He was a hunter and, unlike Allison, he wasn't pack. Family now, but he'd never be pack. 

Stiles tugged gently on Derek's hair, tangling his fingers in it. "You know Allison took her gun with her just now, right?"

"Am I that obvious?" Springs creaked as Derek shifted further down on the sofa so he could look up. 

"Just a lot, dude." For once, Stiles' expression was peaceful. The thousand thoughts and emotions that usually painted it were gone. His heart was steady too, with none of the frantic patter that Derek was used to. Even his scent was subtly different, stripped of most of its usual twist of anxiety. 

He realized he'd lost track of Allison's heartbeat under Stiles' and frowned. "How do you do that?" Stiles raised his eyebrows in question, and Derek clarified, "Go quiet like that? You're not usually the calm one."

"I usually have reason not to be calm." One of Stiles' shoulders lifted in a shrug. "Chris isn't going to ruin his relationship with Allison by trying something. He'll wait until we fuck up first, which isn't going to happen. What's there to worry about?"

There was a slight twist to Stiles' heartbeat, the half-skip of a lie that wasn't a lie, such a small blip that if Derek hadn't been listening he might have missed it. His eyes narrowed. "Really? You're not nervous about anything at all?"

A flutter of sweet adrenaline touched Stiles' scent, and then it was back to the same soothing smoothness. "And I might have been working with Deaton on meditation techniques to control body rhythms," he added, voice still flat and gentle. His fingers on Derek's scalp were just the right amount of firm, tugging without hurting. "I'm surrounded by people who can tell when I'm going to sneeze before I can. It seemed like it might be useful after the babies are born. I've been practicing on Allison. Is it working?"

"It's kind of creepy, actually," Derek admitted, but Stiles' nails dragged along his scalp and he found his eyes drifting closed completely involuntarily. "You smell weird." 

"You're going to appreciate that smell when the teething starts." Long fingers drifted from Derek's scalp down to his temple. The rhythm of Stiles' heart skipped again, then smoothed out. Derek was pretty sure his own heart matched it, but he'd never been very good at listening to himself. "And the late-night screaming Dad keeps warning me about. Deaton says werewolf babies respond to their parents moods a lot more than humans. Are you falling asleep?" 

"Maybe." 

The door ground open and closed with the faint click that meant the lock had been tripped. Derek was so far gone that he didn't open his eyes, just sniffed the air to make sure it was Allison. A minute later the couch dipped, and she was sliding over him to snuggle down between his legs. Her hair tickled the inside of his arm, and her elbow was just sharp enough to be uncomfortable where it was wedged between his hip and the back cushion. He couldn't even care. 

"Good at that, isn't he?" she murmured, rubbing her cheek against his chest. Stiles' hand vanished, and then the other replaced it, and Allison let out a peaceful sigh. Her whole body went limp. 

"It shouldn't even work," Derek grumbled. Tried to grumble. It was hard to speak in anything other than a sleepy mutter. "Shouldn't affect us. Shouldn't affect _you_." 

"Deaton said it's got something to do with being pack." Stiles' voice was breath of a whisper. It ran over Derek's skin, bypassing his ears entirely to settle in his bones and weigh them down. "Won't work in an actual emergency, or during a full moon, though." 

Full moon. It was enough of a reminder that Derek groaned. "We still haven't made plans."

Allison's nose brushed his chest, finding the dip of his collar and nuzzling skin. "Let's go to the lake," she suggested. "Have everyone meet us there."

"Picnic?" Stiles asked, voice soft and far away. "Full moon potluck? We've got leftovers, and we can tell everyone to bring a dish."

"Fine," Derek heard himself say, though he hadn't really meant to. It was hard to think through the tap-tap-tap of fingers on his skin His senses were too sensitive and simultaneously dulled. Every breath, heartbeat and scent registered with pinpoint precision. It just didn't matter beyond the little cocoon of comfort that was the couch. "Call Boyd, and... and I'll... I'll.... shit." Stiles snickered hysterically as Derek reached up and shoved his hand away, then rubbed his face until he didn't feel like he was lost in a cloud. "Stop that if you ever want to leave this couch again."

Stiles ran his fingers through Derek's hair again. "I'll remember that for later," he promised, still laughing.

"If either of you move, I'll get my knife and stab you," Allison threatened lazily. Her ankle twitched. No movement registered beyond that. "Any second now."

Derek settled back onto Stiles' lap again. His heartbeat was still soothing, but without the touches it was easier to think through. "We'll call Boyd in a few minutes. Moonrise isn't until eight. There's no rush." 

"Mmmph," Allison agreed, turning so her face was buried in Derek's chest. "Good idea. Just keep petting me."

Stiles ran his hand through her hair again, giving Derek a wink. "As you wish."

* * *

Derek, Allison and Stiles sat on the shore, well back away from the water, while they waited for the rest of the pack to arrive. The lake was quiet, tinted gold by the sunset over the trees. Every now and then the water rippled, stirred by the late summer breeze. The trees were still in off-season bloom, but now they were mixed with new leaves and old, fruit in every stage of growth. 

Even though the moon hadn't risen yet, Derek could feel it just hours away. It tugged at his bones, made his skin too tight. Far away, he could feel the rest of his pack gathering, the bonds between them thick and tight with the coming night. Erica was a sizzling energy at the back of his throat, tempered by the heavy crush of power that was Boyd. Scott was more distant, a warm buzz of threat and promise. All three of them were threats to be put in their places. His fingers dug into the ground, claws itching to come out, to rend, to protect his position.

Years of practice let him ride it through and stay in control. The two heartbeats beside him kept him grounded, gave him something to focus on that wasn't the thump of instinct in his chest. There was more there than before, something new to the jumping-twist that was Stiles' energy or the still-water, deep-rush of Allison's. _That_ made it easier to relax, too. There was too much at risk to screw this up. 

Taking a deep breath of clean air, Derek leaned into Allison's side and looked out over the lake, counting waves. It took him a moment to realize that the ripples had a new source. One of the mermaids had popped her head out of the water in the distance, watching them. Her coloring made her fade into the water so that Derek had to squint to make her out. He lifted one hand in an acknowledging wave, and she flipped back under, the water barely even splashing as she vanished down into the depths. 

A few minutes later she breached again a few feet out from the shore, where it was still deep enough for her to swim comfortably. Grayish hair floated around her blue-tinted shoulders and partially obscured her breasts, but not enough that Derek couldn't smell Stiles' sudden flare of interest in the situation. As far as Derek could tell, she wasn't one of the leaders, but he couldn't be very certain. They mostly looked alike to him, other than scars and faint color differences. 

When she cocked her head, the webbing around her ears flared, iridescent scales glimmering in the sunlight. "Alpha. Did you bring your mates to play?" she asked in her strangely echoing voice, Her eyes focused hopefully on Allison. "It has been a long time since you swam with us."

Hungry possession tried to claw its way up Derek's chest, and only let itself be shoved back down when Derek reminded himself that _neither_ human would appreciate it. Still, he slid forward a few inches, putting himself between the humans and the water. There hadn't been any problems with the mermaids since they'd talked to them at the start of summer, but he didn't like the way she was eying up Allison. The last thing they needed was to take another dip in mermaid-infested water. "Thank you, but no. It's a full moon. Our pack will be here soon to run with us."

"Oh." The mermaid dipped down, blowing disappointed bubbles. She sulked for a moment before rising up enough to ask, "What of the others? They're not affected by the moon. They can swim?" Her nose wrinkled and she added, "Perhaps the boy?" in a distinctly curious tone.

Allison's hand touched Derek's elbow. "I can't swim right now," she explained easily. "I'm going to have babies. Your water would be bad for us right now." 

Pale eyes went wide. "Oh. _Oh_. It is breeding time for above-waters? So close to winter?" Her eyebrows furrowed in worry, and her webbing shivered. She inched closer to the shore, walking on her palms with her fins splayed out behind her. They'd definitely gotten more colorful since Derek had last seen them, the murky shades turning crimson and purple at the edges. Even her hair was getting brighter, almost turquoise at the ends. "Is safe? Where do you nest in winter? Where is other-mothers?"

"Humans take nine months to gestate—to make babies," Stiles cut in, wiggling forward until he was up beside Derek, and then a little further until his toes were worryingly close to the water. "They won't be here until spring. Derek and I—the Alpha and I are the fathers. The other-mothers?" His hands twisted in the air, obviously trying to figure out how to explain human reproduction to a species that didn't even have males. 

Derek grabbed Stiles' hand before he could accidentally hit something. "Humans only have one mother. The father doesn't carry babies."

The mermaid glanced at him doubtfully. "Is that what above-waters use those for? Strange. Shame." She shivered violently, shedding water droplets. "I will tell—" Her voice pitched into a whistled fragment of sound that scraped Derek's eardrums raw. "Come back before migration." She wiggled back and was gone before Derek could even ask when migration _was_. 

"That was mildly worrying," Stiles said to no one in particular. "Anyone else get the feeling they're planning on kidnapping Allison?"

"Just what I need," Allison muttered. Gravel rolled as she tucked herself behind Derek, wrapping her legs around his waist and crossing her ankles in his lap. Her breasts pressed against his back, and the rest of her was a line of heat just a little warmer than what he'd expect from a human. "If they pull me in, you're coming to get me again, right?" 

He reached over, finding her knee to give it a little squeeze. "I'll start carrying condoms, just in case."

"I didn't need to know that!" Someone out of sight stomped their foot on cement and a woman started laughing—Boyd and Erica in the parking lot, hidden behind the trees. "We'll be there in a few minutes," Boyd continued. "Scott's right behind us. Keep your hands off each other, okay?"

"Don't worry about condoms," Erica added cheerfully, accompanied by the sound of a car door slamming and something—a cooler?—squeaking. "I brought some. And lube. Just in case one of us goes skinny dipping or falls in. _Stiles_." 

Derek rolled his eyes. "The others are almost here," he reported to Stiles and Allison, who were looking at him curiously. "Erica's being a brat."

"I heard that, Hale!" 

"I can almost hear her," Allison commented, seemingly idly. Her hands fisted in the hem of his shirt, and her heart skipped faster. "Just a voice. But I can't make out the words."

Immediately Stiles slid back again, his heart smoothing out to that eerie, slow, not-Stiles rhythm that made Derek shiver. "At least they can't sneak up on you now?"

Before he could get too far with that thing he'd learned from Deaton, Allison shifted over to elbow him. "Stop that. I'm not upset, it's just weird." 

Faintly a car parked, and Scott's voice said, "Maybe it's a full moon thing? I always hear better on a full moon." 

Between Derek's shoulder blades, Allison's head tilted. He felt her smile. "I can hear Scott fine, though."

"Of course you can." Derek squeezed her knee again. She was wearing tights under her dress, thin enough that there might as well have been nothing there at all. "He's Scott." 

The footsteps grew closer and Boyd appeared through the trees to the east carrying a cooler, followed by Erica a second. Scott trailed off to the side, arms piled high with blankets and pillows. Greenery crackled as they dropped the coolers at the edge of the clifflet that marked the start of the beach a good three hundred feet away.

"If you think I'm even going _near_ that water," Scott called, cupping his hands to make the sound carry, "you're wrong! Get over here so we can eat!" 

"We're coming!" Since Allison was already holding on, Derek reached back to loop her arms around his neck. She let out a surprised _eep_ and then clung like a monkey while he rocked upward, balancing against her weight and gravity. Stiles grabbed his shoulders to help haul him up, which somehow turned into clinging to his chest the same way Allison was latched onto his back. 

There was no graceful way to carry two grown adults, so he didn't even try, just lumbered forward one step at a time. Gravel rolled under his feet, digging in through his soles and making balancing even more of a pain in the neck. 

"I feel like a pack mule," he muttered, but he hefted them higher so they wouldn't slip as he walked or, more accurately, waddled. 

"Or the meat in a sandwich," Allison whispered against the nape of his neck. Stiles' teeth scraped the edge of his ear, making his knees almost give way on a tricky bit of gravel. He was starting to reconsider the picnic by the lake idea.

"Stop that," Derek murmured, flushing hot. "Not in front of the pack." 

"Yeah, not in front of the pack." Scott reached over the edge of the cliff when they got close enough and grabbed Stiles by the shoulders, hauling him up and putting him on his feet. "Do we need to have a twelve inch rule or something?" 

"Maybe later," Allison said, squirming around to crawl up the cliff unaided, then turned to help Derek up, whether he needed it or not, pulling and tugging on his arms until he staggered upright and into her arms. Mischief sparkled in her grin. "What do you think, Derek, are we going to need a twelve inch rule?" 

One look at her face was all he needed. "Double it."

* * *

No one fell into the water though Stiles came close once, when the edge of the clifflet started to crumble under his feet. They ate the mass of leftovers everyone had brought, drank the gallons of tea that Boyd's mother swore by, and finished with a packet of cookies each. 

While the last of the cookies were being downed, Derek slipped off and came back on four feet.

He tried to sit at the edge of the blanket but Stiles and Allison yanked him up between them. The full moon rose on a pack of werewolves and their humans sprawled out in sated bliss, covered in crumbs and sandy dirt. It burned in Derek's stomach, made his heart clench and his paws flex. He wanted to sink his teeth into flesh, to feel the first pulse of a new beta or the last beat of a heart. Instead, he rested his chin on his paws and rested, held steady by his pack. The old anger was still there, but it was a dying fire. His pack was solid, strong, growing. There was no reason to let the moon have him. 

"It's a nice night," Allison murmured, leaning her head onto his shoulder. She shivered against Derek, leaning back to watch the moon edge its way over the trees. It reflected in her eyes, just a little too bright to be completely natural. An edge of the wild touched her scent. Derek nudged the top of her head and breathed it in.

Erica rolled over onto her stomach, propping herself up on her elbows and kicking her bare feet up. Her toes were clawed, each sharp tip painted bright pink. "Yeah, it is," she agreed, voice slightly slurred around her teeth. "Wanna go on a run?"

"That'll end well," Boyd muttered into the blanket. He smelled mostly asleep. "She's still human, Erica." 

"Maybe," Allison hummed, eyes still turned upward. Her hands clenched in his fur, nails sliding across his skin. The heat in her scent spiked. It was the only warning she gave before she was up and running, a fleeting shadow against the tree line. 

As one the pack stumbled to their feet, taking off after her on feet and paws. Derek surged to the front, ground sweet and cool under his paws, the moon urging him on in the chase. There was no way Allison could outrun him. Not even a beta werewolf could keep up with a fully turned alpha. 

Of course, Derek wasn't the only one in the running. He didn't get very far before he realized Stiles was falling behind. Pitiful human lungs gasped for air, and he was already soaked with sweat. Derek circled back, circling around Scott and Boyd to come up from behind again, pacing by Stiles' side.

Stiles wasn't trained the way Allison was, couldn't read Derek's body language like a wolf. He didn't get the hint until Derek bounced their shoulders off each other and growled. Even after, Derek had to nearly stop so Stiles could pull himself onto Derek's back, heaving and tugging and generally being completely useless. His seat was bad and he kept slipping too far forward or back; it threw Derek off when they reached the trees and dodging became necessary.

Allison vanished between one step and the next, ducking behind a tree and then never reappearing. The pack scattered, each of them going their own way on the hunt. Nose to the ground, Derek followed her scent back toward the lake, leaving the others behind. On his back Stiles muttered about _fucking werewolves_ and _Allison why_ , but he smelled happy. Sweaty, but happy. 

They lost track of the pack as anything more than a scent, and then, not even that. Allison's trail skittered around the woods, a scent dropped here and there, mostly places where she'd deliberately brushed against a branch. Her heartbeat was close, high with excitement, but Derek couldn't quite catch sight of her.

Wood cracked. Derek whirled. Something dropped out of the trees and slammed into Stiles, knocking him clean off Derek's back. They hit the ground rolling, coming to a stop with Allison on top, grinning down with teeth gone just a little too sharp. 

"Does this mean I win?" she asked breathlessly. The wildness in her scent was thicker, spicier. Leaves scattered through her hair, dirt freckled her nose. "I think this means I win." 

Derek bumped his head against her shoulder, baring his teeth when she looked over at him. He was pretty sure a human shouldn't have been able to see in the dark, with the trees between them and the moon, but Allison grinned back like she wasn't having any trouble with it. 

"Sure, you win," Stiles groaned. His chin tilted up, baring his throat. When Allison dragged her tongue up his adam's apple, he shivered. "What do you win?"

"Erica gave me some of her lube packets." It would have been a non sequitur if she weren't peeling Stiles' shirt off his damp skin. Her hands splayed across his stomach, making the muscles ripple and shiver. "How about a show?"

Raising his eyebrows at her, Derek bent over to nip at her skirt, tugging it up, then pulled at Stiles' jeans for good measure. _That kind of show?_

She grinned again and nodded.

"Hey, watch the teeth." Stiles shoved Derek's muzzle out of the way and started undoing his own pants. His hips lifted so he could pull them down, without ever moving out from between Allison's knees. "All aboard the naked train. Toot, toot." 

Derek snorted, but Allison giggled and reached for the hem of her dress. Her back arched as she pulled it off, dumping it off to the side. Bare skin caught slivers of moonlight through the trees, already slick with sweat from the run. 

Even for a wolf it was dark, but that didn't matter. Derek could smell every movement as his partners undressed, feel the air pressure changes when Stiles stumbled, hear their hearts thundering as hands wandered. He circled, lapping at the drip of salt on their skin, the musk of sex starting to color everything. His cock stiffened in its sheath, slightly cool where it peeked out. 

Allison got Stiles on his back, lube a sharp fake-slick-sweet touch to the air when she ripped open the packet. Her mouth wrapped around his cock, body blocking Derek's view as her fingers slipped between his legs. He still knew the moment she started stretching Stiles out by the way his body arched and his breath stuttered. 

Helpfully, Derek nosed Allison aside until he could reach Stiles' balls. It was one of the places that smelled most like _Stiles_. Not like the things around him but that specific scent that was just _him_ , trapped there in the tangle of coarse hair. He dragged his tongue across them and Stiles whimpered in response. 

One of his knees came up, calf curling around Derek's shoulders, grinding up desperately. "Oh God, oh _God_ , fuck," he gasped. "Really, guys? Double teaming me?" 

Derek slid his nose down until he found Allison's fingers buried to the knuckles in Stiles' ass. When he licked around them, a shudder racked up Stiles' spine. Ears pricked, Derek's tongue pressed in next to Allison's fingers, tasting heat and chemical lubricant and _Stiles_. He lapped at him, working him open in long, broad strokes. Stiles writhed on Allison's fingers, choking on sounds that were so human that they hurt. 

The burn of the moon made Derek's teeth itch and his bones shiver. The back of the thigh was a good place to bite. Solid meat, quick to heal. He _wanted_. Desperately. There were so many things humans couldn't do, so much danger that could steal them away. Temptation tickled through his throat, emerging as a growl. 

It echoed in Allison's throat, slipping out between lips that were still wrapped around the head of Stiles' dick. She pulled off with a wet _pop_. Her teeth sank into the meat of his hip, a burst of bright copper-blood scent erupting into the night air.

Stiles groaned—almost sobbed—and reached down to wrap a tight hand around the base of his cock. "Okay new kink discovered," he gasped. "If we're going to do this, it'd better be soon, or someone's going to have to hold me up." 

Derek pulled away reluctantly, letting his teeth scrape over the inside of Stiles' thigh just to see him shiver. The scent of the lake and the woods muted, veiled by sex and sweat and _them_. He licked down along Stiles' cock, up between his cheeks, before nudging him over. 

Allison's bite painted Stiles' skin in a slick crescent, dots of blood leaking down in thin dribbles. They left it to bleed, pushing Stiles onto his knees and elbows. He was so close to the edge that Allison had to hold him up, after all. She stayed under him, knees bracketing Stiles' ribs, arms around his shoulders while Stiles hid his face just below the faint swell of pregnancy. 

The set-up was obvious. Derek didn't have the vocal chords to laugh, but he still huffed in amusement, baring his teeth over Stiles' shoulder. Allison made a face, silently daring him to judge her. Not that he would. She was obviously better at this than Derek, and he knew better than to fight good results, no matter how they came about. 

His paws slid across bare skin as he wrapped them around Stiles' ribs, claws leaving shallow white-pink scratches no matter how careful he was. Without a hand to guide him his hips rocked awkwardly, cock sliding between Stiles' legs on the first try, and then over his back on the second. 

Fur rubbed backwards as he slid around, looking for just the right angle. Stiles whined, burying his face in Allison's stomach, heart fluttering with growing anticipation. When Derek's cock finally found his hole, Stiles slammed himself back with a loud moan. 

The meat of Stiles' shoulder was too tempting with the moon overhead, so Derek ducked his head and focused on long, smooth strokes instead. It wasn't like fucking Allison as a wolf. Stiles was tighter, but less demanding. As long as Derek didn't stop moving, he just took it. Slow and easy, hard, deep, whatever Derek wanted to give him. His ass clenched, slick and hot, every thrust getting a moan from him that rattled up through Derek's ribs straight into his heart. 

Allison slipped back and shoved Stiles' head between her legs. They lurched together, Stiles' weight lunging forward, the wet sound of his mouth on Allison's cunt joining the slickness of Derek's cock in his ass. She groaned, one hand fisting his hair to hold him in place as she ground against him. The other hand wrapped in Derek's ruff, nails biting in. 

Heat curled up through him, different than the way it did when he was on two feet. It slipped through his chest, built in his stomach and throat, and tingled at the base of his cock. He hopped closer for better balance, slamming in hard. 

Stiles cried out, back arching and come splattering across the leaves and dirt in salt-bitter bursts. His chest and shoulders heaved as he panted for air. Then he ducked his head again, focusing on Allison's cunt so sharply that she collapsed backward. Her back arched, fisting Stiles' hair with both hands as she came, riding his face.

Derek ground in, cock never pulling out more than an inch as he rutted hard into Stiles. His knot swelled and then he was locked in, only able to fuck deeper, harder. The ring of muscle tugged and clenched as he instinctively tried to pull out, and that was it. Pleasure burned, vibrated through his throat and coming free in a whining howl. 

The three of them fell forward, limbs all giving out at once. By some miracle, Derek managed to stay balanced just so, his chin against Stiles' neck, panting as he finished coming. If they all tried, they could probably get him loose. They'd done it once before. He didn't want to try, though, so he arranged himself over the top of them, pinning them down with just enough weight to keep them from getting any ideas about moving. 

Rather than escaping, Allison wiggled until she was even more trapped under Stiles. Her arms came up to wrap around them, hands settling in the fur of Derek's neck, Stiles' face pillowed on her breasts. "Next time, you're going to fuck me while Derek fucks you like this," she told Stiles, sleepy-smug and sated. "Before I get too pregnant for it."

Grunting, Derek turned his head to lick the inside of her forearm in approval. His knot tugged in Stiles as they shifted again, relaxing into each other. The impossible tightness at the base felt like it was receding but Derek knew better than to think it was done yet. 

"You won't get too pregnant for it," Stiles muttered, rubbing his cheek against her breast. "We're smart, flexible, incredibly hot people. We'll figure it out."

Her laugh bounced through Stiles' chest and rattled around in Derek's, sweet as the moon in his bones. "Holding you to that, Stilinski," Allison said fondly. "We're still doing it before we leave for school." 

"Deal."

Huffing, Derek settled his chin on the back of Stiles' neck. He could live with that.

* * *

No one had any interest in cleaning off in the lake, so they did the best they could before trooping back to the blanket. Erica and Boyd were still missing but Scott was there, curled up on his side in a half-doze. Derek laid down beside him and shook, forcing Allison and Stiles to roll lazily to the ground. They groaned in protest, but didn't actually get back up on their feet, which told him he'd made the right choice if he didn't want to play mattress all night. 

Scott peeked at them under the arm he was using as a pillow. His nose wrinkled. "Really, guys?"

Stiles squirmed around until Derek could use his lap for a pillow. He gave Scott a once-over, eyebrows rising. "Really Scott?" he echoed pointedly.

Derek's ears flicked forward curiously. He couldn't see anything wrong with Scott, or smell anything for that matter. The usual scents of pack and dirt and woods laid on his skin, along with a faint hint of the lake. Maybe something else, too. Seaweed or salt, a hint of fish. Nothing strange for being so close to the lake. But from the way Stiles was looking at him, there was definitely something there. 

"What?" Allison stretched out, snuggling into Derek's side. "What did Scott do?" 

"Scott banged a mermaid," Stiles announced. Derek's head came up so fast the world tinted red with alarm

Allison flailed upright, staring at Scott over Derek's back. " _Scott_ ," she gasped, somewhere between delighted and alarmed. "You _didn't_. Did you?" 

Hot-copper embarrassment flooded Scott's scent. "It wasn't like that," he hissed, curling up to hide his face. His heart double-thumped with the lie. Derek's eyebrows rose.

"Either that or Erica and Boyd, because that is definitely your Just Got Laid face." One of Stiles' legs stretched out to nudge Scott's shoulder. "Spill. Admit Stiles knows all."

Embarrassment was a sharp, endless reek now. Scott still didn't uncurl. "She was curious, okay?" he explained, voice muffled by his arms. "There's no such thing as mer-guys, and she wanted to know what the difference was."

"And then you had _sex_." There was a definitely more than a hint of malicious glee in Stiles' voice. "She's half _fish_ , man. At least Derek's got a dick still. I'm pretty sure they lay eggs or something."

With a dramatic flop, Scott rolled over on his back and covered his eyes with an arm. Now that Derek was looking, there was something weird about his skin. A slick, faintly glimmering iridescence running in streaks across his face and down under his shirt collar. "They don't do it like we do. I don't think we even touched— you know, whatever it is they have." 

"But it was sex." Allison wasn't going to let that go either. She crawled up over Derek's back, and while he couldn't see her face, she sounded like she was grinning. "You came, right? And so did she?" 

"Sure, fine, if that's what you want to call it. I had sex with a mermaid, happy? Can I get back to being embarrassed by _your_ awkwardly public sex life now?"

Stretching out his head, Derek nudged Scott's elbow and tried to look empathetic. It got him a head pat which, when he was in full turn, was strangely comforting in a way he would never, ever tell anyone about. 

"Sure," Stiles agreed, kicking Scott gently in the ribs. "But you've forfeited all rights to jokes about what we do with Derek. Mermaid trumps werewolf, dude." 

Scott nodded, ruffling Derek's fur. "If you agree not to make mermaid jokes," he added. The sudden silence from Stiles' said everything that needed saying. Allison muffled her laugher in Derek's side. 

"Do I want to know what they're talking about?" Erica asked from somewhere in the woods. Their footsteps were faint, but getting closer. 

"Probably not," was Boyd's opinion. "Maybe we should stay here."

"They have the food."

"Damn."

Heaving a sigh, Derek dropped his head back to the blanket and closed his eyes. Maybe if he tried really hard, he could get to sleep before Erica got close enough to ask Scott what he did. 

"Hey, Scott, what did the scales feel like on—"

" _Stiles_." 

Or not.


End file.
